Method and device for grinding cooperating faces of friction members



Y.1l coTAL METHOD AND DEVICE FOR GRINDING CQOPERATING FACES 0F P RICTIONMEMBERS Mmh 16, 1943.

Filed lay 31, 1940 2 Sheds-Sheet 1 l J. COTAL March 16, 1943.

AMETHOD AND DEVICE FOR @BINDING cooPERA'rING FACES oF FRIcTIoN MEMBERSFiled May :51, 1940 2 shets-sneet' 2 tlhw m ME.

Patented Mar. 16, 1943 METHOD AND DEVICE FOR GRINDING COOPERATIN G FACEBERS S OF FRICTION MEM- Jean Cotal, Paris, France; vested in the AlienProperty Custodian Application May 31, 1940, lserial No. 338,266 InFrance June 24, 1939 10` Claims.

The present invention relates to a method and apparatus for grinding andhardening elements of magnetic couplings.

In the case of clutches, brakes, speed-changing boxes, and variouscontrolling devices, magnetic discs are coming into increased use, thesebeing coupled by means of electric current.

It has been found preferable, in practice that the surfaces adapted tomake contact for the necessary transmission of power, should besubjected to a preliminary hardening.

The present invention relates to a mechanism adapted for the automaticgrinding, in order to obtain such hardening, of themagnetic discs andtheir cooperating electro-magnets used for clutches, brakes,speed-changing boxes, etc., and of all similar devices.

The said mechanism is chiefly characterized by the fact that'it is soconstructed that the power required for the grinding is produced byvarying the kinetic energy of one or more rotary parts.

Further characteristics will be set forth in the following description.i

' In the accompanying drawings, which are given solely by way ofexample:

l lFig. l is a longitudinal section of a mechanism in .conformity to theinvention which serves for the simultaneous grinding of four groups ofcou# pling devicescomprising magnetic discs and electro-magnets.

Fig. 2 shows a half cross-section on the line 2-2 of Fig. 1, and a halfcross-section on th line 2-2, of the same mechanism.

.Fig 3 is a longitudinal section of another mechanism which serves forthe grinding of boxes having several speeds, provided withelectro-magneticcouplings.

In the embodiment shown in Figs. 1 and 2, the mechanism comprises arotary electro-magnet I mounted on a shaft 2 which is keyed or other`Wise secured to the shaft. of an electric motor 3. The saidelectro-magnet, when excited, can attract an armature 4 which isadjacent the same and is loose on an extended part of the shaft 2. Thesaid armature 4 is secured, as to rotation, to a pinion 6 engagingpinions I which are disposed around this pinion and are secured to themagnetic discs 8 to be ground with the electro-mag nets 9 with whichthey are to cooperate when 'in use. The pinions 'I and the discs 8 areloosely mounted on cylindrical axial extensions I of the electro-magnets9. These latter are mounted on fixed journals II secured to the casingI2 of the mechanism, and each electro-magnet 9 is pregagement of atoothed ring I3 with a xed central pinion I4 secured to the casing ofthe grinding mechanism. The said casing consists, for example,v of twoparts I2 and I2, whose joint is in a vertical plane.

The apparatus operates in oil contained in the said casing. This latteris provided with a pump I5 which withdraws the oil through a conduit IBand discharges it, for instance, into an axial channel I'I. formed inthe driving shaft 2 which is pierced with radial holes I`Ia for thelubrication of the hub of the device and a certain part ofthe oilcirculates into a chamber I8 provided at the end of the shaft 2. Thischamber is connected, for instance by conduits I9, to the journals II,which are hollow and are pierced, as well `asthe hubs of theelectro-magnets, with oil holes 20 adjacent the hubs of the discs 8. l

The direct current required for energizing the various electro-magnetsis supplied by a source of current 2|. The current is distributed by acircular switch 22, Whose rotating arm 23 is connected toone terminal ofthe source of current 2I and is driven by the shaft 2 by means ofpulleys 24 and 25 and a cable 26. The switch arm will send the currentalternately into the electromagnet I connected to the source of currentby a conductor v27, and to the contact pieces 28 of the circular switch22, by a conductor 29, and into the electro-magnets 9 which areconnected to the source of current by conductors 39 and to a second setof contact pieces 3| of the circular switch by conductors 32. i

The operation is as follows. When the electric I motor is set running,the arm 23 which is driven bythe motor shaft, sends the current into theelectro-magnet I, and this latter, by means of the armature 4, drivesthe pinions 6 and I and the armatures 8.

Immediately afterwards, the arm 23 breaks the circuit of theelectro-magnet I and sends current into the fixed electro-magnets 9which brake and stop the armatures 8 and 4, in spite of their kineticenergy. Then continuing its movement, the arm 23 breaks the circuit ofthe electro-mag-` nets 9, and the current is sent ,into theelectromagnet I, which is constantly in rotation, and this latter againdrives the armature 4, and the armatures 8, and the cycle of the drivingand stopping of these armatures is repeated.

During the braking which is required in order to absorb the kineticenergy until the stopping occurs, friction will take place between thefaces vented from rotating on a journal II by the en? of the armatures8` and of the electro-magnets 9, and by reason of this braking action,the surfaces will be ground and hardened.

After a certain number of operations, the discs il and theelectro-magnets 9 are removed for use in clutches, brakes orspeed-changing mechanisms without danger of seizing, in the case of thecouplings for which they are employed.

Itis evident that the said apparatus may comprise if necessary, for thegrinding, a greater number of electro-magnets and armatures such as 8and 9, and that a greater or less speed of grinding for the whole set ofthese pieces can be readily obtained b-y varying the speed of the partssubject to friction, and by varying the weight of certain pieces havinga variable moverment. For instance, it is possible to increase ordiminish the ratio of the gearing 6 and 1I, or to increase or diminishthe weight of the armature 4, and thus to obtain more or less. kineticenergy which is to be absorbed by the grinding work.

The apparatus represented in Fig. 3 comprises, as in Figs. 1 and 2, arevolving electromagnet I secured to the driving shaft 2, which latter,by way of example, is actuated by belt and pulley 33. An armature 4,which may be driven by the electro-magnet I, is secured to the shaft 35,which extends into the grindingbox.

The box shown in the gure is of the known type having two speeds whichare obtained by hypocycloidal gearing which comprises the followingmagnetic parts: anv electro-magnet 34 mounted on the driving shaft 3 5and secured to a main gear-wheel 36 of a planetary set, anelectro-magnet 31 secured to the casing 3&8 of the box, and an armature39 secured to the other main gear wheel 4I] of the planetary set, theplanetary pinion carrier 4I being mounted on the driven shaft 42.

` The box is located in the casing 38 which contains oil and is mountedon the casing I22- of the grinding mechanism.l

' The electro-magnet I is directly connected to the terminals of thesource ofcurrent 2| by conductors 2l; and 43. The electro-magnets 34 andY3'I-1 are connected directly to the source of current 2ly and byconductors Iland 45, to the alternate contact'pieces 46 and 41 of thecircular suritch 22Y whose arm 23 is actuated by the motor rand isconnected to the other terminalof the source of current 2I.

The operation is as follows. During the whole time of they grinding, theelectro-magnet I is excited and it constantly drives the armature 4 andthe electro-magnet 34.

The variation of the kinetic energy, which is necessary for the grindingwork, is produced in this case by varying the speed of the armature 39,which is alternately driven at the speed of the electro-magnets I and 34and stopped by the electro-magnet 3l, as the switch 22 will alternatelyexcite the electro-magnets 34 and 31.

The grinding takes place bythe friction of the surfaces, as in thedevice shown in Fig. 1,l but in this case, the armature 39 has twooperatingfaces. The face adjacent the electro-magnet 34 is ground duringthe engagement of this armature, which proceeds from a Zero speed to thespeed of the electro-magnet 34. The face adjacent the electro-magnet 31-is ground during the braking of this armature, which proceeds from thespeed of the driving shaft to a zero speed.

Obviously, the invention is not limited to the embodiments hereindescribed and represented, which are given solely by way of example.

In the appended claims, the word speed is to be understood for anyabsolute value, either positive, or negative or null.

Having now described my invention, what I claim as new and desire tosecure by Letters Patent is:

1. A method for grinding cooperating faces of members of devicesoperating by friction and particularly of electromagnets and armaturesfor the same which consists in, repeatedly effecting at regularintervals the cycle of operations comprising separating said membersfrom each other, rotating one of said members and maintaining the otherstationary, allowing any one of' said members to rotate freely, andurging said members towards each other so as to bring said cooperatingfaces into close contact whereby said cooperating faces are ground dueto the friction taking place between said faces.

2. A method fory grinding cooperating faces of members of devicesoperating by friction and particularly of electromagnets and armaturesfor the same which consistsin repeatedly effecting at regular intervalsthe cycle of operations comprisingA separating said members from eachother, maintaining one of said members station,- ary and rotating theother member, allowing said other member to rotate freely, and urgingsaid members towards eachother so as to bring said cooperating facesinto close contact whereby said cooperating faces are ground due to thefriction taking place between saidfaces until said members are bothstationary.

3; A method for grinding cooperating faces of members of devicesoperating by friction and particularly of electromagnets and armaturesfor the same which consists in, repeatedly effecting at regularintervals the cycle of' operationsv comprising separating said membersfrom each other, maintaining one of said members stationary and rotatingthe other member, allowing said first member to rotate freely, andurging said members towards each other so as to bring said cooperatingfaces into close contact whereby said cooperating faces are ground dueto the, friction taking place between said faces until saidv membersrotate at the same speed.

fi. A device for grinding cooperating faces of members of devicesoperating by friction and particularly of electromagnets and armaturesyfor the same comprising, driving means, means adapted to supportsaidmembers independently of sai-d drive means with their cooperating facescoaXially disposed, said driving means being adapted to rotate one ofsaid members and retaining means adapted to maintain the other of saidmembers stationary, one Off Said driving and retaining means beingreleasable, releasable at.- trating means adapted tovpresssaidcooperating faces of said members against each other, andcontrolling means adapted to make operative successively andAalternately at regular intervals said two releasable means.

5. A device for grinding cooperating faces of membersof devices.operating by friction andparticularly of electromagnets and armaturesfor the same comprising, meansadaptedto support said members with theircooperating faces coaXially disposed, means adapted to maintain fixedlyone ofA said members, releasable driving means adapted to rotatepositively the other member, releasable attracting means.- adaptedtopresssaid cooperating-- faces of said members against each other, andcontrolling means adapted to make operative successively and alternatelyat regular intervals said driving means and said attracting means.

6. A device for grindingcooperating faces of members of devicesoperating by friction and particularly of electromagnets and armaturesfor the same comprising, means adapted to support said members withtheir cooperating faces coaxially disposed, means adapted to maintainfixedlyone of said members, a driving shaft, electromagnetic clutchmeans having its driving part operatively connected with said drivingshaft and its driven part operatively connected with the other of saidmembers, an electromagnet on one of said members adapted to attract theother member so as to press said cooperating faces of said membersagainst each other, and electric current supplying means includingswitch means adapted to circulate current successively and al ternatelyat regular intervals through said clutch means and through saidelectromagnet.

7. A device for grinding cooperating faces of members of devicesoperating by friction and particularly of electromagnets and armaturesfor the same comprising, a central rotatable shaft, a plurality ofsupporting means distributed about said shaft and each adapted tosupport at least two members to be ground with their cooperating facescoaxially disposed, means adapted to maintain xedly one of said memberson each supporting means, transmission means between said central shaftand the other of said members on each supporting means and adapted totransmit rotation from said shaft to said other member on eachsupporting means, releasable driving means adapted to rotate positivelysaid central shaft, releasable attracting means adapted to press saidcooperating faces of said members against each other on each supportingmeans, and controlling means adapted to make operative successively andalternately at regular intervals said driving means and said attractingmeans.

8. A device for grinding cooperating faces of members of devicesoperating by friction and particularly of electromagnets and armaturesfor the same comprising, means adapted to support said members withtheir cooperating faces co- -axially disposed, driving means adapted torotate one of said members, releasable retaining means adapted tomaintain the other of said members stationary, releasable attractingmeans adapted to press said cooperating faces of said members againsteach other, and controlling means adapted. to make operativesuccessively and alternately at regular intervals said two releasablemeans.

9. A device for grinding cooperating faces of members of devicesoperating by friction and particularly of electromagnets and armaturesfor the same comprising, supporting means adapted to support adjacenteach other three members, two opposite faces to be ground of the centralmember being adapted to cooperate respectively with one adjacent face tobe ground of each of the outer members, releasable attracting means oneach outer member adapted to press the cooperating faces of said outermember and of said central member against each other, driving meansadapted to rotate one of said outer members, retaining means adapted tomaintain stationary the other outer member, and controlling meansadapted to make operative successively and alternately at regularintervals the releasable attracting means on said outer members.

10. A device according to claim 9 in which said attracting means consistof electromagnets and said central member of an armature, and saidcontrolling means consist of electric current supplying means includingswitch means and adapted to successively and alternately at regularintervals energize said electromagnets.

JEAN COTAL.

